ot: the op's situation would be you crush yourself
think about it this way. if your arm is sticking out through the portal, it can collide with yourself. as the portals come closer, your arm is forced into your body
you could avoid getting crushed initially by making sure your appendages stick out through the portal at angles so they dont collide with your body, but eventually the distance gets so small that part of your torso/arm/whatever will stick through one portal and come out the other end, crushing itself in the process. you will be turned into a pulp.